German Battery Firm Sonnen Moves into U.S. Home Solar-Storage Market #Tesla

The U.S. residential energy storage market took another step forward on January 29 when German firm sonnen announced that it was partnering with solar manufacturer SolarWorld to offer residential solar-plus-storage systems in the U.S., much like the systems announced by Tesla and Solar City last April.

Unlike Tesla, however, sonnen has a significant track record with residential storage. The company is the leading supplier in Europe, where it says it has installed more than 10,000 systems since 2011. Part of this is because the German residential electricity market provides rate incentives for home storage that are much less common in the U.S., though some markets such as California are shifting in that direction.

Sonnen is introducing what it calls the sonnenBatterie eco, a battery unit about the size and dimensions of a small refrigerator (Figure 1). The eco is available in capacities of 4 kWh up to 16 kWh, and has an integrated smart inverter and control system allowing it to function as a home microgrid. Within that range, the eco units can be sized in 2-kWh steps.

Sonnen says they are guaranteed for 10,000 cycles or 10 years of use. The batteries are priced at $10,000 for the 4 kWh model up to $24,000 for the 16 kWh model. That’s more than Tesla’s PowerWall home battery, but Greg Smith, sonnen’s senior technical trainer, sought to contrast the eco against the PowerWall by saying the eco is capable of deeper cycling and more total cycles over its lifetime.